Field of the Invention
The present invention relates to an image forming apparatus such as a copier, a printer, or a facsimile machine that uses an electrophotographic system or an electrostatic recording system.
Description of the Related Art
Conventionally, for example, in an image forming apparatus that uses an electrophotographic system, an electrophotographic photosensitive member (photosensitive member) is uniformly charged and is then exposed in accordance with image information, and an electrostatic latent image is thereby formed on the photosensitive member. The electrostatic latent image is developed as a toner image using toner, and is then transferred to a recording material such as recording paper directly or via an intermediate transfer member by a transfer unit. Thereafter, the toner image transferred to the recording material is heated and fixed on the recording material by a fixing unit, and the toner image is thereby formed on the recording material. When the temperature of the toner extremely increases, sticking of the toner occurs due to an increase in the viscosity of the toner. In an image forming apparatus in which a cartridge having a waste toner container for containing waste toner remaining on an image bearing member after transfer is installed, when the temperature of the cartridge increases, the temperature of the waste toner container also increases. When the sticking of the toner in the vicinity of the inlet of the waste toner container occurs due to the increase in the temperature of the waste toner container, the inlet of the container is blocked, and the waste toner is not collected into the waste toner container even when the waste toner is on the photosensitive member. Thus, when the waste toner on the photosensitive member is not collected into the waste toner container, the toner image remains on the photosensitive member, and faulty cleaning that allows an image different from the original toner image to be transferred to the recording material occurs. In addition, when the temperature of a developer container that contains toner used for developing the electrostatic latent image on the photosensitive member increases, the sticking of the contained toner occurs, and degradation of the toner progresses.
In order to prevent the occurrence of faulty cleaning caused by the increase in the temperature of the cartridge, there is proposed a technique disclosed in Japanese Patent Application Publication No. 2007-286579. Japanese Patent Application Publication No. 2007-286579 proposes a configuration in which, in order to prevent the occurrence of the sticking of the toner, the temperature of the cartridge is detected, and the operation of a main body is controlled such that the temperature is not higher than a predetermined threshold temperature such as the glass transition temperature (Tg) of the toner or the like.